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Add CoreDNS as default and remove experimental
This commit is contained in:
Sebastiaan van Steenis
committed by
Denise
Denise
parent
97849f2bc9
commit
cf557022c0
@@ -109,6 +109,16 @@ Instead of using the Rancher UI to choose Kubernetes options for the cluster, ad
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For an example of RKE config file syntax, see the [RKE documentation]({{< baseurl >}}/rke/latest/en/example-yamls/).
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### Default DNS provider
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The table below indicates what DNS provider is deployed by default. See [RKE documentation on DNS provider]({{< baseurl >}}/rke/latest/en/config-options/add-ons/dns/) for more information how to configure a different DNS provider. CoreDNS can only be used on Kubernetes v1.12.0 and higher.
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| Rancher version | Kubernetes version | Default DNS provider |
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|-------------|--------------------|----------------------|
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| v2.2.5 and higher | v1.14.0 and higher | CoreDNS |
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| v2.2.5 and higher | v1.13.x and lower | kube-dns |
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| v2.2.4 and lower | any | kube-dns |
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### Rancher specific parameters
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_Available as of v2.2.0_
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@@ -27,10 +27,12 @@ There are several options that can be configured in cluster configuration option
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* [Authorization]({{< baseurl >}}/rke/latest/en/config-options/authorization/)
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* [Cloud Providers]({{< baseurl >}}/rke/latest/en/config-options/cloud-providers/)
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* [Add-ons]({{< baseurl >}}/rke/latest/en/config-options/add-ons/)
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* [Add-ons Jobs Timeout](#add-ons-jobs-timeout)
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* [Network Plugins]({{< baseurl >}}/rke/latest/en/config-options/add-ons/network-plugins/)
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* [Ingress Controller]({{< baseurl >}}/rke/latest/en/config-options/add-ons/ingress-controllers/)
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* [User-Defined-Add-ons]({{< baseurl >}}/rke/latest/en/config-options/add-ons/user-defined-add-ons/)
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* [Network Plug-ins]({{< baseurl >}}/rke/latest/en/config-options/add-ons/network-plugins/)
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* [DNS providers]({{< baseurl >}}/rke/latest/en/config-options/add-ons/dns/)
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* [Ingress Controllers]({{< baseurl >}}/rke/latest/en/config-options/add-ons/ingress-controllers/)
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* [Metrics Server]({{< baseurl >}}/rke/latest/en/config-options/add-ons/metrics-server/)
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* [User-Defined Add-ons]({{< baseurl >}}/rke/latest/en/config-options/add-ons/user-defined-add-ons/)
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* [Add-ons Job Timeout](#add-ons-job-timeout)
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## Cluster Level Options
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@@ -1,9 +1,64 @@
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---
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title: DNS provider
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title: DNS providers
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weight: 262
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---
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By default, RKE deploys [kube-dns](https://github.com/kubernetes/dns) as DNS provider for your cluster.
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RKE provides the following DNS providers that can be deployed as add-ons:
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* [CoreDNS](https://coredns.io)
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* [kube-dns](https://github.com/kubernetes/dns)
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| RKE version | Kubernetes version | Default DNS provider |
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|-------------|--------------------|----------------------|
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| v0.2.5 and higher | v1.14.0 and higher | CoreDNS |
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| v0.2.5 and higher | v1.13.x and lower | kube-dns |
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| v0.2.4 and lower | any | kube-dns |
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CoreDNS was made the default in RKE v0.2.5 when using Kubernetes 1.14 and higher. If you are using an RKE version lower than v0.2.5, kube-dns will be deployed by default.
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# CoreDNS
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_Available as of v0.2.5_
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CoreDNS can only be used on Kubernetes v1.12.0 and higher.
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RKE will deploy CoreDNS as a Deployment with the default replica count of 1. The pod consists of 1 container: `coredns`. RKE will also deploy coredns-autoscaler as a Deployment, which will scale the coredns Deployment by using the number of cores and nodes. Please see [Linear Mode](https://github.com/kubernetes-incubator/cluster-proportional-autoscaler#linear-mode) for more information about this logic.
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The images used for CoreDNS are under the [`system_images` directive]({{< baseurl >}}/rke/latest/en/config-options/system-images/). For each Kubernetes version, there are default images associated with CoreDNS, but these can be overridden by changing the image tag in `system_images`.
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## Scheduling CoreDNS
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If you only want the CoreDNS pod to be deployed on specific nodes, you can set a `node_selector` in the `dns` section. The label in the `node_selector` would need to match the label on the nodes for the CoreDNS pod to be deployed.
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```yaml
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nodes:
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- address: 1.1.1.1
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role: [controlplane,worker,etcd]
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user: root
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labels:
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app: dns
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dns:
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provider: coredns
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node_selector:
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app: dns
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```
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## Configuring CoreDNS
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### Upstream nameservers
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By default, CoreDNS will use the host configured nameservers (usually residing at `/etc/resolv.conf`) to resolve external queries. If you want to configure specific upstream nameservers to be used by CoreDNS, you can use the `upstreamnameservers` directive.
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```yaml
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dns:
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provider: coredns
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upstreamnameservers:
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- 1.1.1.1
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- 8.8.4.4
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```
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# kube-dns
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RKE will deploy kube-dns as a Deployment with the default replica count of 1. The pod consists of 3 containers: `kubedns`, `dnsmasq` and `sidecar`. RKE will also deploy kube-dns-autoscaler as a Deployment, which will scale the kube-dns Deployment by using the number of cores and nodes. Please see [Linear Mode](https://github.com/kubernetes-incubator/cluster-proportional-autoscaler#linear-mode) for more information about this logic.
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@@ -29,16 +84,6 @@ dns:
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app: dns
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```
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## Disabling kube-dns
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_Available as of v0.2.0_
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You can disable the default DNS provider by specifying `none` to the dns `provider` directive in the cluster configuration. Be aware that this will prevent your pods from doing name resolution in your cluster.
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```yaml
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dns:
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provider: none
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```
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## Configuring kube-dns
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### Upstream nameservers
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@@ -55,16 +100,13 @@ dns:
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- 8.8.4.4
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```
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## CoreDNS (Experimental)
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# Disabling deployment of a DNS provider
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_Available as of v0.2.0_
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If you want to use CoreDNS, you can set the `provider` directive to `coredns`. Both the `node_selector` and `upstreamnameservers` directive is also supported for CoreDNS.
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You can disable the default DNS provider by specifying `none` to the dns `provider` directive in the cluster configuration. Be aware that this will prevent your pods from doing name resolution in your cluster.
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```yaml
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dns:
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provider: coredns
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upstreamnameservers:
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- 1.1.1.1
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- 8.8.4.4
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provider: none
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```
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@@ -185,6 +185,10 @@ addon_job_timeout: 30
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network:
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plugin: canal
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# Specify DNS provider (coredns or kube-dns)
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dns:
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provider: coredns
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# Currently only nginx ingress provider is supported.
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# To disable ingress controller, set `provider: none`
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